1. Field of the Invention
The present invention relates generally to ultraviolet sterilizers having vibration-proof functions and, more particularly, to an ultraviolet sterilizer including an ultraviolet sterilization unit which has an inlet through which ballast water is drawn thereinto, an outlet through which the ballast water is discharged after the ballast water has been sterilized, and an ultraviolet lamp located between the inlet and the outlet, the ultraviolet lamp applying ultraviolet rays to the ballast water to sterilize the ballast water, wherein the ultraviolet sterilizer further includes a cap which supports each of the opposite ends of the ultraviolet sterilization unit, and a shock absorption unit which is elastically compressed at a first end thereof by the cap while a second end thereof elastically compresses a corresponding end of the ultraviolet lamp, whereby even if the ultraviolet sterilization unit vibrates, the sleeve pipe or the ultraviolet lamp can be prevented from being damaged, and explosive gas which may cause the ultraviolet sterilizer to explode is also prevented from entering the cap.
2. Description of the Related Art
Generally, when cargo ships sail with no cargo, ballast water is loaded in tanks of the cargo ships to keep the ships in balance. However, unfortunately, ballast water used in the cargo ships may damage native marine ecosystems because of the foreign marine creatures which have been contained in the ballast water. Therefore, it is required to treat the ballast water. To date, methods of applying ultraviolet rays to ballast water have been widely used.
FIG. 1 is a block diagram of a conventional ballast water treatment system. FIG. 2 is a sectional view showing an ultraviolet sterilizer of the conventional ballast water treatment system. In the conventional ballast water treatment system, a supply pump 11 supplies ballast water to an ultraviolet sterilizer 12, and the ultraviolet sterilizer 12 sterilizes the ballast water and discharges it into a tank 13. A control unit 14 controls the entirety of the system.
In the conventional ultraviolet sterilizer 12, a through hole is formed through a housing cover 121 to facilitate replacement of a sleeve pipe 123 and an ultraviolet lamp 124. A cap 122 is removably coupled to the through hole of the housing cover 121. The cap 122 supports the sleeve pipe 123. The ultraviolet lamp 124 is disposed in the sleeve pipe 123, and a head 1241 of the ultraviolet lamp 124 is supported by a support 125.
However, because a ship having the ultraviolet sterilizer 12 typically sails on the sea and a diesel engine which causes a lot of vibrations is used as a power source for the ship, the ultraviolet sterilizer also creates large vibrations in the longitudinal and lateral directions. Furthermore, the ultraviolet sterilizer sterilizes a large amount of ballast water at a time. Thus, excessive water pressure may be applied to the ultraviolet sterilizer. Here, the support 125 and the ultraviolet lamp 124 are not in close contact with the sleeve pipe 123, in other words, the inner surface of the sleeve pipe 123 is spaced apart from the support 125 and the ultraviolet lamp 124 by a predetermined distance. Therefore, when vibrations are applied to the ultraviolet sterilizer, the support 125 and the ultraviolet lamp 124 may excessively move in the sleeve pipe 123. Typically, the sleeve pipe 123 is made of glass, the head 1241 of the ultraviolet lamp 124 is made of ceramic, and the support 125 is also made of glass. Thus, when the ultraviolet sterilizer vibrates in the lateral direction, the support 125 or the head 1241 of the ultraviolet lamp 124 may collide with the sleeve pipe 123. Thereby, the sleeve pipe 123 or the ultraviolet lamp 124 may be damaged. In addition, when the ultraviolet sterilizer vibrates in the longitudinal direction, impacts applied to the cap 122 are directly transmitted to the ultraviolet lamp 124 through the support 125. Thereby, the support 125 collides with the head 1241 of the ultraviolet lamp 124, thus damaging the ultraviolet lamp 124 or the support 125 or the ultraviolet lamp 124.
Moreover, several devices or machines are present around the ultraviolet sterilizer. Particularly, explosive gas may be present around the ultraviolet sterilizer. If explosive gas enters the cap 122, the ultraviolet sterilizer may be exploded by a spark.